1 //===-- llvm/Attributes.h - Container for Attributes ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief This file contains the simple types necessary to represent the
12 /// attributes associated with functions and their calls.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_IR_ATTRIBUTES_H
17 #define LLVM_IR_ATTRIBUTES_H
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/DenseSet.h"
21 #include "llvm/ADT/FoldingSet.h"
30 class AttributeSetImpl;
31 class AttributeSetNode;
36 //===----------------------------------------------------------------------===//
38 /// \brief Functions, function parameters, and return types can have attributes
39 /// to indicate how they should be treated by optimizations and code
40 /// generation. This class represents one of those attributes. It's light-weight
41 /// and should be passed around by-value.
44 /// This enumeration lists the attributes that can be associated with
45 /// parameters, function results, or the function itself.
47 /// Note: The `uwtable' attribute is about the ABI or the user mandating an
48 /// entry in the unwind table. The `nounwind' attribute is about an exception
49 /// passing by the function.
51 /// In a theoretical system that uses tables for profiling and SjLj for
52 /// exceptions, they would be fully independent. In a normal system that uses
53 /// tables for both, the semantics are:
55 /// nil = Needs an entry because an exception might pass by.
56 /// nounwind = No need for an entry
57 /// uwtable = Needs an entry because the ABI says so and because
58 /// an exception might pass by.
59 /// uwtable + nounwind = Needs an entry because the ABI says so.
62 // IR-Level Attributes
63 None, ///< No attributes have been set
64 AddressSafety, ///< Address safety checking is on.
65 Alignment, ///< Alignment of parameter (5 bits)
66 ///< stored as log2 of alignment with +1 bias
67 ///< 0 means unaligned (different from align(1))
68 AlwaysInline, ///< inline=always
69 ByVal, ///< Pass structure by value
70 InlineHint, ///< Source said inlining was desirable
71 InReg, ///< Force argument to be passed in register
72 MinSize, ///< Function must be optimized for size first
73 Naked, ///< Naked function
74 Nest, ///< Nested function static chain
75 NoAlias, ///< Considered to not alias after call
76 NoCapture, ///< Function creates no aliases of pointer
77 NoDuplicate, ///< Call cannot be duplicated
78 NoImplicitFloat, ///< Disable implicit floating point insts
79 NoInline, ///< inline=never
80 NonLazyBind, ///< Function is called early and/or
81 ///< often, so lazy binding isn't worthwhile
82 NoRedZone, ///< Disable redzone
83 NoReturn, ///< Mark the function as not returning
84 NoUnwind, ///< Function doesn't unwind stack
85 OptimizeForSize, ///< opt_size
86 ReadNone, ///< Function does not access memory
87 ReadOnly, ///< Function only reads from memory
88 ReturnsTwice, ///< Function can return twice
89 SExt, ///< Sign extended before/after call
90 StackAlignment, ///< Alignment of stack for function (3 bits)
91 ///< stored as log2 of alignment with +1 bias 0
92 ///< means unaligned (different from
94 StackProtect, ///< Stack protection.
95 StackProtectReq, ///< Stack protection required.
96 StackProtectStrong, ///< Strong Stack protection.
97 StructRet, ///< Hidden pointer to structure to return
98 UWTable, ///< Function must be in a unwind table
99 ZExt, ///< Zero extended before/after call
101 EndAttrKinds, ///< Sentinal value useful for loops
103 AttrKindEmptyKey, ///< Empty key value for DenseMapInfo
104 AttrKindTombstoneKey ///< Tombstone key value for DenseMapInfo
107 AttributeImpl *pImpl;
108 Attribute(AttributeImpl *A) : pImpl(A) {}
110 Attribute() : pImpl(0) {}
112 //===--------------------------------------------------------------------===//
113 // Attribute Construction
114 //===--------------------------------------------------------------------===//
116 /// \brief Return a uniquified Attribute object.
117 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
118 static Attribute get(LLVMContext &Context, StringRef Kind,
119 StringRef Val = StringRef());
121 /// \brief Return a uniquified Attribute object that has the specific
123 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align);
124 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align);
126 //===--------------------------------------------------------------------===//
127 // Attribute Accessors
128 //===--------------------------------------------------------------------===//
130 /// \brief Return true if the attribute is an Attribute::AttrKind type.
131 bool isEnumAttribute() const;
133 /// \brief Return true if the attribute is an alignment attribute.
134 bool isAlignAttribute() const;
136 /// \brief Return true if the attribute is a string (target-dependent)
138 bool isStringAttribute() const;
140 /// \brief Return true if the attribute is present.
141 bool hasAttribute(AttrKind Val) const;
143 /// \brief Return true if the target-dependent attribute is present.
144 bool hasAttribute(StringRef Val) const;
146 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This
147 /// requires the attribute to be an enum or alignment attribute.
148 Attribute::AttrKind getKindAsEnum() const;
150 /// \brief Return the attribute's value as an integer. This requires that the
151 /// attribute be an alignment attribute.
152 uint64_t getValueAsInt() const;
154 /// \brief Return the attribute's kind as a string. This requires the
155 /// attribute to be a string attribute.
156 StringRef getKindAsString() const;
158 /// \brief Return the attribute's value as a string. This requires the
159 /// attribute to be a string attribute.
160 StringRef getValueAsString() const;
162 /// \brief Returns the alignment field of an attribute as a byte alignment
164 unsigned getAlignment() const;
166 /// \brief Returns the stack alignment field of an attribute as a byte
168 unsigned getStackAlignment() const;
170 /// \brief The Attribute is converted to a string of equivalent mnemonic. This
171 /// is, presumably, for writing out the mnemonics for the assembly writer.
172 std::string getAsString() const;
174 /// \brief Equality and non-equality operators.
175 bool operator==(Attribute A) const { return pImpl == A.pImpl; }
176 bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
178 /// \brief Less-than operator. Useful for sorting the attributes list.
179 bool operator<(Attribute A) const;
181 void Profile(FoldingSetNodeID &ID) const {
182 ID.AddPointer(pImpl);
186 //===----------------------------------------------------------------------===//
188 /// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by
190 template<> struct DenseMapInfo<Attribute::AttrKind> {
191 static inline Attribute::AttrKind getEmptyKey() {
192 return Attribute::AttrKindEmptyKey;
194 static inline Attribute::AttrKind getTombstoneKey() {
195 return Attribute::AttrKindTombstoneKey;
197 static unsigned getHashValue(const Attribute::AttrKind &Val) {
200 static bool isEqual(const Attribute::AttrKind &LHS,
201 const Attribute::AttrKind &RHS) {
206 //===----------------------------------------------------------------------===//
208 /// \brief This class holds the attributes for a function, its return value, and
209 /// its parameters. You access the attributes for each of them via an index into
210 /// the AttributeSet object. The function attributes are at index
211 /// `AttributeSet::FunctionIndex', the return value is at index
212 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at
221 friend class AttrBuilder;
222 friend class AttributeSetImpl;
223 template <typename Ty> friend struct DenseMapInfo;
225 /// \brief The attributes that we are managing. This can be null to represent
226 /// the empty attributes list.
227 AttributeSetImpl *pImpl;
229 /// \brief The attributes for the specified index are returned.
230 AttributeSetNode *getAttributes(unsigned Idx) const;
232 /// \brief Create an AttributeSet with the specified parameters in it.
233 static AttributeSet get(LLVMContext &C,
234 ArrayRef<std::pair<unsigned, Attribute> > Attrs);
235 static AttributeSet get(LLVMContext &C,
236 ArrayRef<std::pair<unsigned,
237 AttributeSetNode*> > Attrs);
239 static AttributeSet getImpl(LLVMContext &C,
240 ArrayRef<std::pair<unsigned,
241 AttributeSetNode*> > Attrs);
244 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {}
246 AttributeSet() : pImpl(0) {}
247 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {}
248 const AttributeSet &operator=(const AttributeSet &RHS) {
253 //===--------------------------------------------------------------------===//
254 // AttributeSet Construction and Mutation
255 //===--------------------------------------------------------------------===//
257 /// \brief Return an AttributeSet with the specified parameters in it.
258 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs);
259 static AttributeSet get(LLVMContext &C, unsigned Idx,
260 ArrayRef<Attribute::AttrKind> Kind);
261 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B);
263 /// \brief Add an attribute to the attribute set at the given index. Since
264 /// attribute sets are immutable, this returns a new set.
265 AttributeSet addAttribute(LLVMContext &C, unsigned Idx,
266 Attribute::AttrKind Attr) const;
268 /// \brief Add attributes to the attribute set at the given index. Since
269 /// attribute sets are immutable, this returns a new set.
270 AttributeSet addAttributes(LLVMContext &C, unsigned Idx,
271 AttributeSet Attrs) const;
273 /// \brief Remove the specified attribute at the specified index from this
274 /// attribute list. Since attribute lists are immutable, this returns the new
276 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx,
277 Attribute::AttrKind Attr) const;
279 /// \brief Remove the specified attributes at the specified index from this
280 /// attribute list. Since attribute lists are immutable, this returns the new
282 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx,
283 AttributeSet Attrs) const;
285 //===--------------------------------------------------------------------===//
286 // AttributeSet Accessors
287 //===--------------------------------------------------------------------===//
289 /// \brief Retrieve the LLVM context.
290 LLVMContext &getContext() const;
292 /// \brief The attributes for the specified index are returned.
293 AttributeSet getParamAttributes(unsigned Idx) const;
295 /// \brief The attributes for the ret value are returned.
296 AttributeSet getRetAttributes() const;
298 /// \brief The function attributes are returned.
299 AttributeSet getFnAttributes() const;
301 /// \brief Return true if the attribute exists at the given index.
302 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
304 /// \brief Return true if attribute exists at the given index.
305 bool hasAttributes(unsigned Index) const;
307 /// \brief Return true if the specified attribute is set for at least one
308 /// parameter or for the return value.
309 bool hasAttrSomewhere(Attribute::AttrKind Attr) const;
311 /// \brief Return the alignment for the specified function parameter.
312 unsigned getParamAlignment(unsigned Idx) const;
314 /// \brief Get the stack alignment.
315 unsigned getStackAlignment(unsigned Index) const;
317 /// \brief Return the attributes at the index as a string.
318 std::string getAsString(unsigned Index) const;
320 typedef ArrayRef<Attribute>::iterator iterator;
322 iterator begin(unsigned Idx) const;
323 iterator end(unsigned Idx) const;
325 /// operator==/!= - Provide equality predicates.
326 bool operator==(const AttributeSet &RHS) const {
327 return pImpl == RHS.pImpl;
329 bool operator!=(const AttributeSet &RHS) const {
330 return pImpl != RHS.pImpl;
333 //===--------------------------------------------------------------------===//
334 // AttributeSet Introspection
335 //===--------------------------------------------------------------------===//
337 // FIXME: Remove this.
338 uint64_t Raw(unsigned Index) const;
340 /// \brief Return a raw pointer that uniquely identifies this attribute list.
341 void *getRawPointer() const {
345 /// \brief Return true if there are no attributes.
346 bool isEmpty() const {
347 return getNumSlots() == 0;
350 /// \brief Return the number of slots used in this attribute list. This is
351 /// the number of arguments that have an attribute set on them (including the
352 /// function itself).
353 unsigned getNumSlots() const;
355 /// \brief Return the index for the given slot.
356 uint64_t getSlotIndex(unsigned Slot) const;
358 /// \brief Return the attributes at the given slot.
359 AttributeSet getSlotAttributes(unsigned Slot) const;
364 //===----------------------------------------------------------------------===//
366 /// \brief Provide DenseMapInfo for AttributeSet.
367 template<> struct DenseMapInfo<AttributeSet> {
368 static inline AttributeSet getEmptyKey() {
369 uintptr_t Val = static_cast<uintptr_t>(-1);
370 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
371 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
373 static inline AttributeSet getTombstoneKey() {
374 uintptr_t Val = static_cast<uintptr_t>(-2);
375 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
376 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val));
378 static unsigned getHashValue(AttributeSet AS) {
379 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
380 (unsigned((uintptr_t)AS.pImpl) >> 9);
382 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
385 //===----------------------------------------------------------------------===//
387 /// \brief This class is used in conjunction with the Attribute::get method to
388 /// create an Attribute object. The object itself is uniquified. The Builder's
389 /// value, however, is not. So this can be used as a quick way to test for
390 /// equality, presence of attributes, etc.
392 DenseSet<Attribute::AttrKind> Attrs;
393 std::map<std::string, std::string> TargetDepAttrs;
395 uint64_t StackAlignment;
397 AttrBuilder() : Alignment(0), StackAlignment(0) {}
398 explicit AttrBuilder(uint64_t Val) : Alignment(0), StackAlignment(0) {
401 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) {
404 AttrBuilder(AttributeSet AS, unsigned Idx);
405 AttrBuilder(const AttrBuilder &B)
407 TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()),
408 Alignment(B.Alignment), StackAlignment(B.StackAlignment) {}
412 /// \brief Add an attribute to the builder.
413 AttrBuilder &addAttribute(Attribute::AttrKind Val);
415 /// \brief Add the Attribute object to the builder.
416 AttrBuilder &addAttribute(Attribute A);
418 /// \brief Add the target-dependent attribute to the builder.
419 AttrBuilder &addAttribute(StringRef A, StringRef V);
421 /// \brief Remove an attribute from the builder.
422 AttrBuilder &removeAttribute(Attribute::AttrKind Val);
424 /// \brief Remove the attributes from the builder.
425 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index);
427 /// \brief Remove the target-dependent attribute to the builder.
428 AttrBuilder &removeAttribute(StringRef A);
430 /// \brief Add the attributes from the builder.
431 AttrBuilder &merge(const AttrBuilder &B);
433 /// \brief Return true if the builder has the specified attribute.
434 bool contains(Attribute::AttrKind A) const;
436 /// \brief Return true if the builder has the specified target-dependent
438 bool contains(StringRef A) const;
440 /// \brief Return true if the builder has IR-level attributes.
441 bool hasAttributes() const;
443 /// \brief Return true if the builder has any attribute that's in the
444 /// specified attribute.
445 bool hasAttributes(AttributeSet A, uint64_t Index) const;
447 /// \brief Return true if the builder has an alignment attribute.
448 bool hasAlignmentAttr() const;
450 /// \brief Retrieve the alignment attribute, if it exists.
451 uint64_t getAlignment() const { return Alignment; }
453 /// \brief Retrieve the stack alignment attribute, if it exists.
454 uint64_t getStackAlignment() const { return StackAlignment; }
456 /// \brief This turns an int alignment (which must be a power of 2) into the
457 /// form used internally in Attribute.
458 AttrBuilder &addAlignmentAttr(unsigned Align);
460 /// \brief This turns an int stack alignment (which must be a power of 2) into
461 /// the form used internally in Attribute.
462 AttrBuilder &addStackAlignmentAttr(unsigned Align);
464 // Iterators for target-independent attributes.
465 typedef DenseSet<Attribute::AttrKind>::iterator iterator;
466 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator;
468 iterator begin() { return Attrs.begin(); }
469 iterator end() { return Attrs.end(); }
471 const_iterator begin() const { return Attrs.begin(); }
472 const_iterator end() const { return Attrs.end(); }
474 // Iterators for target-dependent attributes.
475 typedef std::pair<std::string, std::string> td_type;
476 typedef std::map<std::string, std::string>::iterator td_iterator;
477 typedef std::map<std::string, std::string>::const_iterator td_const_iterator;
479 td_iterator td_begin() { return TargetDepAttrs.begin(); }
480 td_iterator td_end() { return TargetDepAttrs.end(); }
482 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
483 td_const_iterator td_end() const { return TargetDepAttrs.end(); }
485 /// \brief Remove attributes that are used on functions only.
486 void removeFunctionOnlyAttrs() {
487 removeAttribute(Attribute::NoReturn)
488 .removeAttribute(Attribute::NoUnwind)
489 .removeAttribute(Attribute::ReadNone)
490 .removeAttribute(Attribute::ReadOnly)
491 .removeAttribute(Attribute::NoInline)
492 .removeAttribute(Attribute::AlwaysInline)
493 .removeAttribute(Attribute::OptimizeForSize)
494 .removeAttribute(Attribute::StackProtect)
495 .removeAttribute(Attribute::StackProtectReq)
496 .removeAttribute(Attribute::StackProtectStrong)
497 .removeAttribute(Attribute::NoRedZone)
498 .removeAttribute(Attribute::NoImplicitFloat)
499 .removeAttribute(Attribute::Naked)
500 .removeAttribute(Attribute::InlineHint)
501 .removeAttribute(Attribute::StackAlignment)
502 .removeAttribute(Attribute::UWTable)
503 .removeAttribute(Attribute::NonLazyBind)
504 .removeAttribute(Attribute::ReturnsTwice)
505 .removeAttribute(Attribute::AddressSafety)
506 .removeAttribute(Attribute::MinSize)
507 .removeAttribute(Attribute::NoDuplicate);
510 bool operator==(const AttrBuilder &B);
511 bool operator!=(const AttrBuilder &B) {
512 return !(*this == B);
515 // FIXME: Remove this in 4.0.
517 /// \brief Add the raw value to the internal representation.
518 AttrBuilder &addRawValue(uint64_t Val);
521 namespace AttributeFuncs {
523 /// \brief Which attributes cannot be applied to a type.
524 AttributeSet typeIncompatible(Type *Ty, uint64_t Index);
526 } // end AttributeFuncs namespace
528 } // end llvm namespace